This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. NMR Spectroscopy The samples were deuterium exchanged by dissolving in D2O and lyophilization. The samples were dissolved in 80 [unreadable]L D2O, 5 [unreadable]L 1 % acetone in D2O was added as internal reference, and the samples were placed in a 3 mm Shigemi NMR tube. 1-D Proton, TOCSY and NOESY NMR spectra, run with water presaturation, and gradient enhanced COSY and HSQC spectra were acquired on a Varian Inova-600 MHz spectrometer at 25 [unreadable]C. Chemical shifts were measured relative to internal acetone ([unreadable]H=2.218 ppm, [unreadable]C=33.00 ppm). Standard Varian acquisition parameters were used;some variable parameters are listed in Table 1.